Safety cable reel



Feb. 24, 1942. P. HAMMOND SAFETY CABLE REEL 2 Sheets-Sheet 1 Filed Oct. 24, 1940 IIJlllHlhl I 1 II IIIH AAU/RE/VCE P HAMMOND L. P. HAMMOND SAFETY CABLE REEL 2 Sheets-Sheet 2 Filed Oct. 24, 1940 Patented Feb. 24, 1942 SAFETY CABLE REEL Laurence P. Hammond, Spengler, Pa. Application October 24, 1940, Serial No. 362,689 3 claims. (01-200-153) This invention relates to an improved safety cable reel and more particularly to a cable reel for use'with'shot-ilr'ing apparatus.

One object of the invention is to provide a safety cable reel which is of such construction that a shot-firing batterycannot be connectedwlth the terminals of the cable associated with the reel until said cable has been completely unwound from said reel.

A still further object of the invention is to provide a device of this character which is characterized by simplicity of construction.

A further object of the invention is to provide a safety cable reel having a hub mounting contact prong for engagement with a shot-firing battery, said prong being short eircuited at all times except when the battery is in engagement therewith so that danger of accidental firing will be eliminated.

Other objects of the invention, not mentioned hereinbefore, will becomeapparent during the course of the following description.

In the drawings:

Figure 1 is a side elevation of my improved safety cable reel,

Figure 2 is a front view thereof,

Figure 3 is a vertical sectional view, partly in elevation, of my improved safety cable reel, and showing particularly the. construction 01' the reel drum Or spool,

Figure 4 is a transverse sectional view on the line 44 of Figure 3, looking in the direction indicated by the arrows, and

Figure 5 is an enlarged detail sectional view better showing the contact prong construction.

Referring now more particularly to the drawings, wherein like numerals of reference will be seen to designate similar parts throughout theviews, the numeral I indicates in general the frame of my improved safety cable reel. The frame I includes a base 2, which base has side bars 3 and 4 and, at the corresponding opposite ends of said side bars, end bars I and 9. As best seen in Figure 1, the side bars 9 and 4 are under cut at their ends to receive said and bars I and I, the end bars projecting downwardly past the horizontal plane of the lower edges of the side bars to define feet I.

The frame I includes spaced parallel uprights I and}, said uprights being mounted on the side bars 3 and 4, respectively, substantially medially thereof, and rising therefrom at right angles to the base 2. The uprights 9 and 9 may be connected to the side members 3 and 4 by step joints, as shown in dotted lines at HI in Figure 3, or

in any other suitable manner. The uprights 8 and 9 are formed with slots H at their corresponding upper ends, and said slots receive the corresponding opposite ends of a handle l2, said handle serving the two-fold purpose of providing means whereby the reel may be conveniently carried and providing connecting means for the corresponding upper ends of the uprights. Bolts II extend through the upper end portions '01 the uprights and through the ends of the handle l2 for firmly anchoring the handle in place.

Rotatably mounted on the frame 1 between the uprights 8 and 9 and the side members 3 and 4 is a spool l4. The spool I4 is most clearly seen in Figure 3 of the drawings and includes circular end plates I5 and I9 and an axial hub IT. The hub is fixed on a shaft III to rotate therewith, said shaft having end portions journaled in the uprights 9 and 9 so that, as will be clearly seen, the spool will be free to rotate within the confines of the frame. The shaft I9 is projected at H to receive a crank 20, for permitting convenient rotation of the spool.

The huh I], as best seen in Figures 3, 4 and 5, is formed with a recess 2|, said recess having a slot 22 formed in its bottom wall. Mounted within the recess 2| on the bottom wall thereof, and in straddling relation to the slot 22, are prong-supporting plates 23 and 24, said prongsupporting plates being held in place on the hub II by means of screws 29. The prong-supporting plates carry spaced alined contact prongs 26 which project upwardl within the recess 2| substantially medially between the walls thereof.

In order to short circuit the prongs 26, to prevent accidental shot-firing, I provide a short circuiting bar 21, said bar being formed of resilient material and having one end secured to the.-

prong-supporting plate 24. The short circuiting bar is mounted within the slot 22 and is provided with an integral upwardly projecting finger 29, for engagement with a battery, in a manner to be set forth in more detail hereinafter.

'As seen iniFigure l. the'short circuiting bar norshown in Figure 2, when not in use.

While it is thought that the operation of the invention will be clearly understood, a brief description thereof is not thought to be out of Place.

when the cable 30 is wound about the spool H, as shown in Figure 2, the device may be transported from place to place conveniently. Moreover, when the cable is in the position mentioned, it will not be possible to make electrical connection to the prongs 28. After the free end of the cable has been connected with a charge of explosive to be set off, it will be necessary to unwind the cable completely from the spool in order to expose the prongs 26. When this is done, logically, the operator will be a safe distance from the charge. Also, when the cable is unwound from the spool l4, and the prongs 26 are exposed, it will be possible for the operator to engage the contacts of a shot-firing battery 34 with said prongs 26, for setting off the charge. As best seen in Figure 5, as the shot-firing battery I is moved down upon the prongs 25, the finger 28 is engaged by the surface of the battery, and said finger is pushed downwardly for moving the free end of the short circuiting bar out of engagement with the plate 23. This is, of course, necessary to allow current to pass from the prongs through the plates and through the cable 30 to the battery. As soon as the battery is moved, the cable is again short circuited by the short circuiting bar 21 which, of course, moves upwardly for engaging the free ends thereof with the plate 23 immediately upon removal of pressure of the battery from the finger 28.

It is believed that the construction and operation of my invention will now be completely understood and that I have provided a simple and highly efficient safety cable reel which will largely eliminate accidents, such as might be caused by setting off a charge before the operator has reached a safe distance therefrom.

Having thus described the invention, what is claimed as new is:

1. In a safety cable reel, a spool having a hub formed with a recess, prong-supporting plates carried in the recess, contact prongs thereon, a cable wound about the hub and having wires connected with the prong-supporting plates, and means rotatably mounting the spool, said contact prongs being engageable with battery terminals for feeding electric current into the cable only after said cable has been entirely unwound from about the hub, and means normally short circuiting the prongs, said means being displaceable upon engagement of the prongs with said battery terminals.

2. In a safety cable reel, a frame, a spool rotatably mounted in the frame and having a recess and a slot communicating with the recess, prongsupporting plates mounted within the recess, prongs on the plates and projecting upwardly within the recess, a short circuiting bar in the slot and having one end thereof connected with one of the prong-supporting plates, said short circuiting bar having a battery-engaging finger, and a cable normally wound about the hub and having wires electrically connected with the prong-supporting plates, said prongs being engageable with the terminals of a battery only after said cable has been unwound from about the hub, said short circuiting bar normally short circuiting the prongs, said finger being engageable by the battery for breaking the short circuit when said battery is in position on the prongs. 1

3. In a safety cable reel, a spool having ahub, a cable wound around the spool. a pair of prongs on the hub and connected with the cable and permitting electrical connection to the cable by a battery only after said cable has been unwound from the spool, and a short circuiting bar carried by the hub and normally connected between th prongs for short circuiting the cable, said short circuiting bar having a finger engageable with a portion of said battery and being displaceable from short circuiting position by movement of the battery to engagement with the prongs.

LAURENCE P. HAMMOND. 

